Entryway systems used in building construction generally include a pair of vertically extending door jambs and a head jamb that frame the entryway and receive a hinged door. An elongated threshold assembly is attached at its ends to the bottoms of the door jambs and spans the bottom of the entryway atop a sub-sill and/or sub-floor. Many modern threshold assemblies include an extruded aluminum sill frame. These extruded frames often include an upwardly open channel from which a sill slopes outwardly and downwardly. A threshold cap, which may be made of plastic or wood, is disposed in the upwardly open channel and underlies a closed door mounted in the entryway. The threshold cap usually is vertically adjustable to meet and form a seal with a flexible seal attached to the bottom of the door.
Threshold assemblies are typically mounted atop a wooden or concrete sub-sill and/or sub-floor. The forward portions of the threshold assemblies often overhang a front face of the sub-sill and/or sub-floor and outwardly extend above an adjacent underlying structure such as sheathing, finished siding material or brick masonry. One important design parameter for threshold assemblies is to minimize if not eliminate intrusion of moisture under the front edges of the thresholds. Intruding water may damage an underlying wooden sub-floor and sub-sill.
In addition, the forward edges of extruded aluminum sill frames often are provided with functional yet unattractive configurations. For example, extruded sill frames may include one or more recesses, notches, grooves, or other features for optional mating engagement with extruded sill extensions or other attachments.
Accordingly, there is a need for a seal that reduces or eliminates the possibility of moisture reaching the wooden frame members underlying a threshold assembly, and also provides an attractive finished appearance to an irregularly shaped front edge of a doorsill.